Fluke Flashcards
What are the names of the liver flukes, rumen flukes and lancet fluke?
Common liver fluke
* Fasciola hepatica
* Fasciola gigantica
Rumen fluke
* Paramphistomum spp.
* Calicophoron daubneyi
Lancet fluke
* Dicrocoelium dendriticum
What are the characteristics of fluke?
- Indirect life cycle
- Dorso-ventrally flattened
- Hermaphrodite
- No body cavity
- Tegument
What does fluke effect in an animal?
- Growth rate
- Milk yield
- Wool and fibre
- Liver condemnation
What are the definitive hosts of fluke?
- Ruminants
- Camelids
- Wild animal reservoir (hares, rabbits, deer)
- Horses
- Humans
What are the intermediate hosts of F. hepatica and F. gigantica?
- F. hepatica –amphibious mud snails
- F. gigantica –water snails
Galba Truncatula
What are the 2 types of infection, what does this depend on?
acute + chronic
depends on number of metacercariae ingested and
the time period over which they are ingested
What is acute fasciolosis?
- Immature/juvenile migrating flukes
- Large numbers
- Usually only occurs in sheep in UK
- October –December
Multifocal necrotic or haemorrhagic
tracts throughout the liver
What is the pathogenesis of acute fasciolosis?
- Migration of immature flukes through the liver parenchyma
- Haemorrhagic tracts
- Inflammation
- Liver enlargement
- Fibrosis
What are the clinical signs of acute fasciolosis?
- Sudden death
- Weakness/dullness
- Abdominal pain
- Anaemia
What is chronic fasciolosis?
- Occurs in sheep and cattle
- Low numbers of metacercariae ingested over longer period of time
- Adult flukes in bile ducts
- Disease in late winter/early spring –January-March
What is the pathogenesis of chronic fasciolosis?
- Adult flukes feeding on blood in bile ducts
- Spines on the tegument irritate bile duct walls
- Hyperplasia of the bile ducts
- Fibrosis & calcification (cattle)
- Cholangitis
What are the clinical signs of chronic fasciolosis?
- Progressive weight loss
- Anaemia
- Sub-mandibular oedema
- Ascites
What is sub-acute fasciolosis and what are the clinical signs?
Sheep ingest metacercariae over a longer period of time
Disease caused by both immature/juvenile and adult flukes
Typical clinical signs
* Rapid weight loss
* Anaemia
What is likely to happen during a warm wet summer regarding fluke?
Three warm wet months
* Large numbers of cercariae released on pasture in September
* Large numbers of metacercariae on pasture, ingested by sheep
* Acute disease 2-6 weeks later
What is likely to happen during a cool dry summer regarding fluke?
Cool, dry summer
* Fewer metacercariae produced
* Released gradually from snails between September and November
* Chronic disease in winter and early spring the following year
